Diarthroidial joints such as the knee permit mobility and movement in people and animals via a complex structure containing interacting and interdependent elements such as articular cartilage, bone, ligaments, tendons, synovium, the joint capsule, vasculature, nerves and other soft tissues. The joint is considered to be an organ that fulfils this function of permitting movement and mobility when healthy, but can be subject to disease and degeneration of its various structures mentioned above. Joint disease is often referred to as arthritis and there are two major forms of arthritis, osteoarthritis and rheumatoid arthritis, the latter bearing a more inflammatory aspect than the former, while the former is much more prevalent, affecting up to 15% of the population in developed countries.
Although the etiology and pathogenesis of the various forms of arthritis are not entirely understood, most of these disease states lead to a painful joint that has significant damage to articular cartilage, often with areas of articular cartilage that are entirely denuded down to subchondral bone. Since articular cartilage provides the smooth nearly frictionless surface that permits joint loading and protects subchondral bone from direct articulation, degeneration of articular cartilage is considered a hallmark and common endpoint of joint disease that requires treatment, often in the form of prosthetic joint replacement.
Current methodologies that are applied by clinicians to assess joint function and disease include physical examination and imaging technologies such as magnetic resonance imaging or computed tomography.
Although these techniques provide a wealth of information, none have been able to provide sensitive and specific diagnostic information early enough in the disease process to permit successful interventions and development of therapeutics that are effective prior to end-stage disease.
It would thus be highly desirable to be provided with a method for diagnosis degeneration of articular cartilage and joint disease at stages that are treatable, prior to necessitating joint replacement.